Roller blind



FIG. 1 is a perspective view of a roller blind, showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is an opposite side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The portions shown in broken lines depict environment that forms no part of the claimed design; and

The break lines shown in FIGS. 1-5 symbolize breaks in the length of the article in which the claimed design is embodied. The appearance of any portion of the article between the break lines forms no part of the claimed design. 

CLAIM We claim, the ornamental design for a roller blind, as shown and described. 